Speculation

Flower Power may have the ability to prevent or stall a conflict.Erf-b1-p013 It may also directly affect plant life. When we first see Sizemore and Janis, they are sitting next to a giant flower. Might Janis have grown that flower to its huge size during Sizemore's lesson? If Flower Power allows casters to quickly grow giant plants, then they could prevent conflicts by growing barriers of giant plants between conflicting sides.

Flower Power may also have limited control over plant life.

Sizemore mentions that "in the presence of so much Flower Power, time perception sort of crumbles". The Hippiemancers call it "Flaking".Erf-b1-p011

1) To speculate on Flower Power, let's note that there are few references at this time, but we may infer certain aspects from its sister Classes and Disciplines and the evidence we have. Flower Power is the confluence of Life, Matter, and Erf, Classes and Axis respectively, which places it in the Discipline of Hippiemancy. (It may be worth noting, Flower Power might also be defined by the absence of Motion from its Classes.) The use of magic in other Disciplines of Erf are well known to Erfworld fans, such as Dirtamancy, Lookamancy, and on at least two explosive occasions, Shockmancy. The Erf Axis schools for their Disciplines appear to be strongly physically based as might be inferred from the Erf Axis. In this way, Flower Power might also be physically grounded in Erf for the Hippiemancy Discipline. The sense in which is related to the confluence of Life and Matter may be that it deals with the ways that living beings (life) experience their physical environment (matter). For example, Flower Power Flaking appears to impact the experience of time. In the one example we have, this effect was experienced as physical time dilation [1] in a localized space within a single hex and not by beings outside of that space, however, for Signamancers it would appear that Flower Power's sister Discipline in Erf, Turnamancy, may be required to impact turn-based time between hexes or perhaps sides. Based on visual references and the deference of Janis, Grand Abbie, to the plight of others, Flower Power may stress communitarian/egalitarian values which it may share with its fellow Hippiemancy Disciplines, Signamancy and Date-a-mancy. Looking for inferences into Flower Power from it's sister Disciplines, Signamancy and Date-a-Mancy does not provide much additional evidence at this time as they too are not locked in much Canon. With their confluence of Life and Matter and their absence of Motion Classes, it may be that within Hippiemancy Flower Power (Erf) might influence the environment/nature (space), Signamancy [2] (Fate) might influence perspective/insight (vision), and Date-a-mancy [3] (Numbers) might influence synchronicity (time in meaningful events, or put another way, the inverse of meaningful events in time).

2) Hippiemancy is the magic of relationships: detecting and altering the forces of opposition and attraction which bind people or units. Flower power may relate most to bending and breaking the rules of Erfworld using loopholes; and distort perception of time. If Parson is flower power capable and spent an entire night wishing that units could move at night, he might have been able to move only at night from that day onward (explaining his failure to walk out during the day) yet not realizing his newfound abilities.

3) If Flower Power has control over plants it may help improve (or possibly destroy) food production.

If this is true, then theoretically Flower Power may also grant bonuses when leading plant based units, such as Gumps, in the same way that a Croakamancer grants bonuses to uncroaked units that he or she is leading.

4) Flower power may also be related to herbalism on Stupidworld.

5) Flower Power may allow its practitioners to manufacture various forms of drugs, both helpful and harmful in nature.

6) If poisons are Flower Power, then perhaps antidotes to those poisons may be as well.

Real World References

"Flower Power" was a slogan used by the 1960's-70's peace movement whose practitioners were known as Hippies, or Flower Children.